1. Field of the Invention
The present invention relates to the field of beaming of elastomeric yarn by unwinding the yarn from cakes in a creel and winding, or beaming, the elastomeric yarn onto a beam in a beaming apparatus.
2. Description of the Related Art
Elastomeric yarn is made by spinning yarn and winding the spun yarn onto a tube to form a cake of elastomeric yarn. Manufacturers of fabrics that include elastomeric yarn require a large number of ends of yarn in order use the yarn in machines to make a fabric, and therefore it is necessary to wind, or warp, a large number of ends from cakes onto a beam to knit or weave the elastomeric yarn into warp-stretch fabrics.
Machines for warping elastomeric yarn are known in the art. Turning to FIG. 1, there is shown a conventional beaming apparatus 11 that include a creel 13, a pre-stretch unit 15, and a warper head 17. Elastomeric yarn is unwound from a large number of cakes 19 in creel 13 where pre-stretch unit 15 produces the pulling force necessary to unwind the yarn from the cakes. The yarn is wound onto a beam in warper head 17.
Creel 13 includes a plurality of cakes, usually from 1000 to 1600. As shown in FIG. 2, cakes 19 have a central core, or tube, 21 around which elastomeric yarn 23 is wound. Typically, creel 13 includes at least one frame with cakes 19 mounted on each frame in long horizontal or vertical rows and in a number of levels or stories above one another. Creel 13 often includes more than one frame in which case the frames are spaced apart either parallel to each other or in some other configuration. Each cake 19 is mounted on a rotatable spool or drive roll and the outer circumferential surface of cake 19, that is, elastomeric yarn 23, is placed in contact with a drive roll 25 that drives the surface of cake 19 in a speed ratio of 1:1 to unwind cake 19. While being unwound, yarn 23 is also subject to a pulling force from pre-stretch unit 15.
Pre-stretch unit 15 includes rolls 27 which pull yarn 23 from creel 13 at a pulling force necessary to assure optimal unwinding of yarn 23. If the pulling force is too high or too low, yarn 23 will unwind incorrectly.
Yarn 23, as it is unwound, typically passes through a thread guide 31 which orients yarn 23 approximately 90 degrees toward pre-stretch unit 15. Thread guide 31 is generally in the shape of a loop called a pigtail, and is made from ceramic.
As yarn 23 exits creel 13, unwound yarn 23 from one level or row of cakes 19 passes through a front guide 33 to orient yarns 23 into a thread sheet. As the threadsheet enters pre-stretch unit 15, yarn 23 is aligned by a separation comb 35 before passing onto rollers 27.
Yarn 23 passes from pre-stretch unit 15 through a reed 37 and then to beam 29. Reed 37 is a comb-like structure that has a base and a plurality of needles connected to the base so as to define spaces therebetween through which the each of yarns 23 from creel 13 are threaded.
A conventional beaming apparatus as described above typically operates at unwinding speeds of about 170 meters per minute, depending on the yarn. As will be explained in greater detail below, there are inherent problems with such conventional beaming apparatuses which are solved by the present invention.
The inventive apparatus includes the following features: a rotating guide, an elastomeric yarn unwinder assembly that includes a guide support that supports rotating guides and a movable buggy for transporting wound cakes of elastomeric yarn to the guide support, a metal thread guide, a front guide and tension bar assembly and a pivoting reed.
The inventive rotating guide for unwinding elastomeric yarn from a stationary cake of wound elastomeric yarn includes a disk, a connector portion formed in the disk to allow the disk to be connected to means for rotating the disk, an aperture formed in the surface of the disk between the connector portion and the outer edge of the disk to allow elastomeric yarn to pass therethrough as the disk is rotated and elastomeric yarn is unwound from the cake, and means in the aperture for controlling the pulling force on an elastomeric yarn pulled through the aperture so that if the elastomeric yarn is unwinding freely from the cake the pulling force is decreased and if the elastomeric yarn is not unwinding freely from the cake the pulling force is increased. In one embodiment the pulling force control means includes a top ring, middle ring and bottom ring stacked together in the aperture, each of the rings having an opening formed therein, the middle ring having a projection formed therein that extends into the opening thereof so as to partially cover the openings in the top and bottom rings and that extends in a direction away from the direction of rotation of the rotating guide, wherein the width of the middle ring around the perimeter of the opening formed therein is less than or equal to the width of the corresponding portions of the top and bottom rings.
The invention also relates to an elastomeric yarn unwinder assembly which includes a rotating guide having a disk, a connector portion formed in the disk to allow the disk to be connected to means for rotating the disk, and an aperture formed in the surface of the disk between the connector portion and the outer edge of the disk to allow elastomeric yarn to pass therethrough as the disk is rotated and elastomeric yarn is unwound from the cake, means for rotating the rotating guide attached to the connector portion, and a stationary cake of elastomeric yarn positioned adjacent to the rotating guide. The rotating guide of the unwinder assembly may also include means in the aperture as described above for controlling the pulling force on an elastomeric yarn pulled through the aperture so that if the elastomeric yarn is unwinding freely from the cake the pulling force is decreased and if the elastomeric yarn is not unwinding freely from the cake the pulling force is increased.
The elastomeric yarn unwinder assembly may also include a guide support having at least one arm extending outwardly therefrom, the means for rotating a rotating guide being attached to the arm so as to support the rotating means and the rotating guide on the guide support, and a tray supported on the guide support and positioned below the rotating guide so as to support a stationary cake of elastomeric yarn below the rotating guide. The assembly may also include a movable buggy adapted to mate to the guide support having at least one arm formed therein which extends outwardly therefrom, the stationary cake of elastomeric yarn being supported on the buggy arm such that when the buggy is mated to the guide support the stationary cake of elastomeric yarn is supported below the rotating guide.
Another feature of the invention is a thread guide assembly for use in a beaming apparatus which includes a thread guide having a top portion and a bottom portion, the top portion having a loop formed therein to hold a thread of yarn, a base member attached to the bottom portion of the thread guide so that the top portion of the thread guide may be moved under tension, and means in the base member for detecting an increase in tension on the thread guide so that the tension detecting means provides an indication if the tension on the thread guide exceeds a predetermined amount.
Still another feature of the invention is a thread guide for use in a beaming apparatus, which guide has a loop formed therein to hold a thread of yarn, wherein the thread guide includes a surface-hardened metal.
Another feature of the invention is a front guide and tension bar assembly for use in a beaming apparatus which includes a bar having a plurality of guides formed therein for allowing yarn to be threaded therethrough, and means connected to the bar for measuring the pressure on the bar caused by the force of yarn on the bar as yarn is pulled through the guides in the bar. The assembly may also include output means for receiving a signal from the pressure measuring means and providing a measurement of the pressure on the bar and pressure monitoring means for receiving a signal of the pressure from the output means, comparing the pressure to a range of desired pressure values, and sending a signal to an output means if the pressure on bar falls outside the range of desired pressure values.
The invention also relates to a method for unwinding a cake of wound yarn by unwinding the yarn in a creel according to a revolution control over end take off method, passing the yarn through a front guide, measuring the pressure on the front guide caused by the force of yarn on the front guide as yarn is pulled therethrough, and beaming the yarn onto a beam which is rotated in a warper head wherein the speed of rotation of the over end roll may be controlled based upon the pressure on the front guide on the bar.
Another feature of the invention is a reed for use in a beaming apparatus includes a bar having a plurality of needles formed therein, and means connected to the bar for pivoting the bar in at least a horizontal plane.